In the related art, there is a known endoscope apparatus in which a reflected-light image and a fluorescence image of an observation subject are acquired, one of the images is displayed in a main window on a monitor, and the other image is displayed in a subwindow (for example, see Patent Literature 1). In addition, there is also a known endoscope apparatus in which a reflected-light image and a fluorescence image are displayed in a superimposed manner (for example, see Patent Literature 2).
In the process of inserting the inserted portion of an endoscope into the body of a patient, an observer, such as a doctor or the like, performs the insertion task by mainly using the reflected-light image, and, in the process of observing the vicinity of a diseased portion, the observer observes mainly the fluorescence image.